1. Field of the Invention
The present invention relates to an image forming apparatus and, in particular, to an image forming technique for reducing visibility of concentration unevenness on an image which is generated by crosstalk of an inkjet head.
2. Description of the Related Art
As a general-purpose image forming apparatus, an inkjet recording apparatus for ejecting ink from multiple nozzles provided in an inkjet head and forming an image on paper (recording medium) has been known. The inkjet recording apparatus causes piezoelectric elements corresponding to the respective nozzles on the basis of image data to operate to eject ink from the nozzles.
Higher density arrangement of nozzles in conformity with a demand for improving the quality of an image to be formed, in turn, arranges the piezoelectric elements corresponding to the respective nozzles at high density. As a result, the operation of any piezoelectric element causes crosstalk that affects the ejection efficiency (ejection performance) of nozzles arranged adjacent thereto.
Occurrence of concentration unevenness on an image caused by occurrence of crosstalk degrades the image quality. In order to achieve image forming at high quality, occurrence of crosstalk is required to be suppressed to, in turn, suppress variation in ejection efficiency of each nozzle.
Crosstalk at the inkjet head is roughly classified into mechanical crosstalk and acoustic wave crosstalk. The mechanical crosstalk is a phenomenon where propagation of vibrations in an operation of a piezoelectric element to another piezoelectric element varies the operation state of the other piezoelectric element (e.g., the amount of variation of piezoelectric element) and, as a result, the ejection efficiency (ejection performance) varies.
The acoustic wave crosstalk is a phenomenon where transmission of acoustic waves in ink propagates to another nozzle, and varies the ejection efficiency (ejection performance) of the other nozzle.
Japanese Patent Application Laid-Open No. 2008-143023 describes an inkjet recording apparatus (inkjet printer) including an inkjet head (inkjet recording head) in which multiple nozzles are arranged in a matrix.
The inkjet recording apparatus described in this document includes an air damper provided in a manifold in an inkjet head such that vibrations due to ink ejection do not affect another nozzle (for preventing crosstalk).